"You can reset Internet Explorer settings to return them to the state they were in when Internet Explorer was first installed on your PC. This can be useful for troubleshooting problems that might be caused by settings changed after installation. Resetting Internet Explorer isn't reversible, and all previous settings are lost after the reset.
To have us reset Internet Explorer settings for you, go to the "Reset Internet Explorer for me" section. If you would rather reset Internet Explorer settings yourself, see how to do it in the "Let me reset Internet Explorer myself" section."Apparently Bookmarks are preserved despite what they imply. Just in case though I would export them to make a backup copy